In the prior art, position sensitive detectors (PSDs) have used high-performance HgCdTe infrared material for an absorber layer, as described by R. Wolfshagen, et al. in “HgCdTe Position Sensitive Detector (PSD) Development” by Oceanit Laboratories Inc. 2010. Using HgCdTe infrared material for an absorber layer requires very expensive substrates that are not available in large diameter. Attempts have been made to grow HgCdTe on silicon substrates for low cost and large format arrays; however, the resulting epi quality has high defect densities. The prior art also relies on processes for fabrication of II-VI material, which are processes that are immature and expensive compared to III-V processes.
In the prior art position sensitive detectors (PSD) use PN junction devices, which require low temperature operation to reduce both diffusion and generation-recombination currents. For example, InSb material can be used for PSD arrays, but needs to be operated at 77 degrees Kelvin, and suffers from a short wave infrared (SWIR) cutoff. InGaAs PN junction-based PSD arrays are commercially available, but are useful for only the visible to near infrared (NIR) wavelengths. HgCdTe material is presently used for extended wavelengths such as mid wave infrared (MWIR), but using HgCdTe material is expensive, as discussed above.
What is needed is a position sensitive detector that is low cost and high performance, which can operate from the short wave infrared (SWIR) to mid wave infrared (MWIR) wavelengths. The embodiments of the present disclosure answer these and other needs.